Mr. Brooks, water is not a commodity, it is common property. It is vital to all life. It is not manufactured for sale, it is provided by our environment, but in limited supply. Conservation and sustainable distribution when scarcity is present make sense.   Reserving the supply for those who can pay, does not.

A minimal supply of usable water, accessible to all citizens, is a public health service and the cost of its delivery should be funded as such. (Food growing must be allowed a certain amount of water on the same basis, and regions may also support local industries by allotting them a portion of water. Above a basic quantity per user of water, market pricing could be fairly applied, as long as license for such use remains a privilege, not a right to water, and the water supply always remains in the public domain.)

Kent, private land is not essential in the way that water is. Many communities try to supply basic amounts of food to those without means to grow or buy it. Supplying water is technically more difficult (e.g. it's usually easier to supply unlimited quantities through a pipe than share it out) but all the more vital.

If we could agree on the thresholds separating scarcity from abundance, we could in theory sustain any amount of exploitation of any public resource while surplus is available. However, that creates a temptation to believe, "There is a surplus," as long as possible. As Canada's cod fishery debacle demonstrates, humans with the best will in the world, and all the research in the world, are still embedded in a psychological and political environment which will systemically select for research, results, conclusions, and personnel which favour near-term benefit and externalise costs. Even the smallest pull, if sustained, will change the course of the largest ship; so, even the tiniest bias will gradually change the behaviour of the whole system if far-sighted decision making (e.g. conservation) is rewarded less than short-term thinking (e.g. profit now).

Is there any place on earth where limited water supplies are shared equitably among humans without sacrificing the local ecology's health?

Peace, if those Ice Age meltwater pools we call the Great Lakes contain 22% of Earth's fresh surface water, that doesn't mean we have a fifth of the freshwater supply. Only 2% of that water comes from yearly precipitation. The rest of it is non-renewable: draw down the water table too fast and it won't come back. (Remember the Aral Sea?)